3.[14 28]space vector based dual zero-vector random centered distribution pwm algorithm for direct torque control of induction motor drive for reduced acoustical noise
This document presents a novel dual zero-vector random centered distribution PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive to reduce acoustic noise. The proposed algorithm uses two zero voltage vectors (V0 and V7) and selects one randomly based on the operating modulation index. Simulation results show the DZRCDPWM algorithm reduces acoustic noise harmonics compared to the conventional SVPWM algorithm by distributing the pulse patterns randomly. The DZRCDPWM provides better performance over the entire modulation index range for induction motor drive control with reduced acoustic noise.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
The document presents a hybrid pulse width modulation (HPWM) method for voltage source inverter (VSI) fed induction motor drives. It proposes a generalized PWM (GPWM) algorithm that varies a constant to generate different discontinuous PWM (DPWM) algorithms along with the space vector PWM (SVPWM) algorithm. The GPWM approach uses instantaneous phase voltages to calculate inverter gating times, reducing complexity compared to the classical SVPWM approach. Simulation results show that SVPWM gives better performance at low modulation indices, while DPWM is better at higher indices. Therefore, the paper presents a HPWM algorithm to achieve superior waveform quality across all modulation indices.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses techniques for mitigating conducted electromagnetic interference (EMI) in DC-DC converter topologies. It analyzes three random pulse width modulation techniques - Randomized Trailing Edge with Randomized Pulse Width Modulation, Randomized Trailing Edge with Randomized Pulse Position Modulation, and Constant Trailing Edge with Randomized Duty Ratio and Randomized Pulse Position Modulation with Fixed Carrier Frequency. Analytical derivations of the power spectral density are presented for each technique. The techniques aim to spread harmonic power in the frequency domain and reduce electromagnetic interference without using additional hardware components.
This document summarizes a research paper on implementing hysteresis control for space vector pulse width modulation (SVPWM) inverters. It begins by introducing SVPWM and total harmonic distortion (THD). It then describes the principles of SVPWM, including determining switching times and patterns. Next, it defines the hysteresis band control method using a relay function. The document proceeds to model the inverter and describe the switching interval generator and control signal generator blocks. Finally, it provides an overview of the simulation model, which combines hysteresis control with SVPWM.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...IAES-IJPEDS
The aim of this paper to presents a comparative analysis of Voltage Source
Inverter using Sinusoidal Pulse Width Modulation Method, Third Harmonic
Injection Pulse Width Modulation Method and Space Vector Pulse Width
Modulation Two level inverter for Induction Motor. In this paper we have
designed the Simulink model of Inverter for different technique. An above
technique is used to reduce the Total Harmonic Distortion (THD) on the AC
side of the Inverter. The Simulink model is close loop. Results are analyzed
using Fast Fourier Transformation (FFT) which is for analysis of the Total
Harmonic Distortion. All simulations are performed in the MATLAB
Simulink / Simulink environment of MATLAB.
ECG Signal Compression Technique Based on Discrete Wavelet Transform and QRS-...CSCJournals
The document presents a new ECG signal compression technique based on discrete wavelet transform (DWT) and QRS-complex estimation. The technique first estimates the QRS-complex from the ECG signal, then subtracts it to form an error signal. This error signal is wavelet transformed, and the coefficients are thresholded based on energy packing efficiency to maximize compression ratio and minimize distortion. Testing on MIT-BIH records showed the technique achieves high compression ratios of 25.15 with low distortion levels of 0.7% PRD.
The document proposes a direct torque control (DTC) method for induction motors that combines space vector modulation (SVM) and an adaptive stator flux observer. It aims to preserve the fast dynamic response of DTC while improving steady-state performance and reducing torque ripple through SVM. An adaptive flux observer is designed using state feedback control theory to ensure stability and robustness. Simulation results validate the effectiveness of the proposed DTC-SVM approach with PI control and an adaptive flux observer in reducing torque ripple compared to conventional DTC.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
The document presents a hybrid pulse width modulation (HPWM) method for voltage source inverter (VSI) fed induction motor drives. It proposes a generalized PWM (GPWM) algorithm that varies a constant to generate different discontinuous PWM (DPWM) algorithms along with the space vector PWM (SVPWM) algorithm. The GPWM approach uses instantaneous phase voltages to calculate inverter gating times, reducing complexity compared to the classical SVPWM approach. Simulation results show that SVPWM gives better performance at low modulation indices, while DPWM is better at higher indices. Therefore, the paper presents a HPWM algorithm to achieve superior waveform quality across all modulation indices.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses techniques for mitigating conducted electromagnetic interference (EMI) in DC-DC converter topologies. It analyzes three random pulse width modulation techniques - Randomized Trailing Edge with Randomized Pulse Width Modulation, Randomized Trailing Edge with Randomized Pulse Position Modulation, and Constant Trailing Edge with Randomized Duty Ratio and Randomized Pulse Position Modulation with Fixed Carrier Frequency. Analytical derivations of the power spectral density are presented for each technique. The techniques aim to spread harmonic power in the frequency domain and reduce electromagnetic interference without using additional hardware components.
This document summarizes a research paper on implementing hysteresis control for space vector pulse width modulation (SVPWM) inverters. It begins by introducing SVPWM and total harmonic distortion (THD). It then describes the principles of SVPWM, including determining switching times and patterns. Next, it defines the hysteresis band control method using a relay function. The document proceeds to model the inverter and describe the switching interval generator and control signal generator blocks. Finally, it provides an overview of the simulation model, which combines hysteresis control with SVPWM.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...IAES-IJPEDS
The aim of this paper to presents a comparative analysis of Voltage Source
Inverter using Sinusoidal Pulse Width Modulation Method, Third Harmonic
Injection Pulse Width Modulation Method and Space Vector Pulse Width
Modulation Two level inverter for Induction Motor. In this paper we have
designed the Simulink model of Inverter for different technique. An above
technique is used to reduce the Total Harmonic Distortion (THD) on the AC
side of the Inverter. The Simulink model is close loop. Results are analyzed
using Fast Fourier Transformation (FFT) which is for analysis of the Total
Harmonic Distortion. All simulations are performed in the MATLAB
Simulink / Simulink environment of MATLAB.
ECG Signal Compression Technique Based on Discrete Wavelet Transform and QRS-...CSCJournals
The document presents a new ECG signal compression technique based on discrete wavelet transform (DWT) and QRS-complex estimation. The technique first estimates the QRS-complex from the ECG signal, then subtracts it to form an error signal. This error signal is wavelet transformed, and the coefficients are thresholded based on energy packing efficiency to maximize compression ratio and minimize distortion. Testing on MIT-BIH records showed the technique achieves high compression ratios of 25.15 with low distortion levels of 0.7% PRD.
The document proposes a direct torque control (DTC) method for induction motors that combines space vector modulation (SVM) and an adaptive stator flux observer. It aims to preserve the fast dynamic response of DTC while improving steady-state performance and reducing torque ripple through SVM. An adaptive flux observer is designed using state feedback control theory to ensure stability and robustness. Simulation results validate the effectiveness of the proposed DTC-SVM approach with PI control and an adaptive flux observer in reducing torque ripple compared to conventional DTC.
This document describes a simulation of a space vector PWM controller for a five-level voltage-fed inverter motor drive. It begins by introducing multilevel inverters and some of the challenges in controlling them, specifically the increased complexity with more levels. It then presents a new approach to implementing space vector PWM for a five-level inverter by treating it as a conventional two-level system, making the calculations simpler. The methodology and implementation are described, including estimating switching times. Simulation results are presented showing the current, voltage and THD waveforms both with and without an LC filter. It is concluded that the proposed 2D system approach allows for simple implementation of SVPWM for a five-level inverter using common D
This document discusses using artificial neural networks to solve the harmonics elimination problem in three-phase voltage-controlled inverters. It presents a new training algorithm for an ANN that does not use pre-computed switching angles from classical harmonic elimination methods. Instead, it trains the ANN by using the desired solution of the harmonic elimination equations, with the first harmonic equal to the modulation index and higher harmonics equal to zero. Theoretical analysis and simulation results show the high performance of using this ANN approach for generating optimal switching functions to control harmonics in inverters.
Space Vector Modulation with DC-Link Voltage Balancing Control for Three-Leve...IDES Editor
Modified space vector modulation (SVM) for
DC-link voltage balancing of three-level inverter is proposed
here. Effect of the DC-link capacitor voltage deviation on
inverter switching states is presented for three-level
inverter. Pulse pattern arrangements for proposed SVM
using degree of freedom available in choice of redundant
space vectors, sequencing of vectors, and splitting of duty
cycles of vector are best exploited. Seven-segment SVM
scheme and modified closed loop space vector DC-link
voltage balancing control schemes are implemented. The
effectiveness of proposed scheme is verified by simulations
and experimental verification on laboratory prototype.
This document presents space vector based generalized discontinuous pulse width modulation (GDPWM) algorithms for voltage source inverter (VSI) fed induction motor drives. The proposed algorithms aim to reduce the complexity of sector identification and angle calculation involved in conventional space vector PWM (CSVPWM). GDPWM uses the concept of imaginary switching times and variables like modulation phase angle δ and constant μ to generate modulation waveforms. Simulation results in MATLAB/Simulink show that the proposed GDPWM algorithms reduce current ripple compared to CSVPWM and different GDPWM sequences produce different total harmonic distortion levels in the motor current.
MODELLING AND IMPLEMENTATION OF AN IMPROVED DSVM SCHEME FOR PMSM DTCpaperpublications3
This document discusses modelling and implementing an improved direct self control (DSC) scheme for permanent magnet synchronous motors (PMSMs) using discrete space vector modulation (DSVM). It begins with an overview of field oriented control and direct torque control techniques for PMSMs. It then presents the PMSM model and basic direct torque control scheme. Issues with the basic DTC scheme like torque and flux ripples are discussed. The document reviews the existing DSVM DTC technique and proposes a new DSVM DTC scheme for PMSMs that takes motor speed and torque/flux errors into account. Comparisons of performance and switching losses between basic DTC and improved DSVM DTC are made through simulation and experiments.
This document summarizes a research paper that proposes modeling direct torque control of an inverter-fed induction motor as a hybrid system using discrete event modeling.
The paper first describes direct torque control and its issues with high torque ripple and variable switching frequency when using hysteresis comparators. It then presents a three step method: 1) Modeling direct torque control as a hybrid system with discrete voltage vector events and continuous flux and torque dynamics. 2) Abstracting the continuous dynamics as discrete events like flux entering/exiting regions. 3) Using supervisory control theory to control the induction motor.
The document focuses on modeling the inverter and induction motor as a discrete event system to address issues with direct torque control,
A Refined Space Vector PWM Signal Generation for Multilevel InvertersIDES Editor
A refined space vector modulation scheme for
multilevel inverters, using only the instantaneous sampled
reference signals is presented in this paper. The proposed
space vector pulse width modulation technique does not require
the sector information and look-up tables to select the
appropriate switching vectors. The inverter leg switching times
are directly obtained from the instantaneous sampled
reference signal amplitudes and centers the switching times
for the middle space vectors in a sampling time interval, as in
the case of conventional space vector pulse width modulation.
The simulation results are presented to a five-level inverter
system for dual-fed induction motor drive. The dual-fed
structure is realized by opening the neutral-point of the
conventional squirrel cage induction motor. The five-level
inversion is obtained by feeding the dual-fed induction motor
with four-level inverter from one end and two-level inverter
from the other end.
Optimal Coordination of DOCR for Radial Distribution Systems in Presence of TCSCIJPEDS-IAES
Protective relays coordination is the process of determining the exact relay
settings such that the relay closes to the fault would operates faster than other
relays. The operating time of each relay depends on two independent
variables called Pickup current (Ip) and Time Dial Setting (TDS). In this
paper, a PSO algorithm has been presented to determine the coordination of
Directional Over-Current Relays (DOCRs) in presence of multi-system
FACTS devises. From the simulation result and analysis, the impact of TCSC
location in the in 33-bus distribution system on Directional Over-Current
Relays has been observed on the optimal relays settings as well as the
effectiveness of the proposed algorithm in finding optimal coordination of
directional over-current relays.
Fast svm based 3 phase cascaded five level invertereSAT Journals
Abstract Introduction of nearest three vector algorithm is a major achievement in the area of space vector technology. Complexity and severe computations are still the drawbacks of SVM methods mainly for multilevel inverter applications. A fast SVM technique is introduced in this project which allows the calculation of switch time duration and the efficient determination of switching times based on the two level inverter scheme. SVM modulating waves are generated based on the two level system and then this modulating waves are compared with required number of carrier signals in order to generate the switching pulses for the inverter. Four triangular carrier signals are needed for a five level system in order to generate the switching pulses. Coordinates of the nearest three voltage vectors is not needed, so the complexity of the SVM technique can be reduced and it is the major advantage of the proposed technique compared with conventional SVM techniques used for multilevel inverters. A three phase five level cascaded H bridge topology is used here to verify the effectiveness of the proposed technique. MATLAB simulation and hardware implementation of the proposed system is done. From the analysis of both simulation and hardware it is clear that proposed SVM technique have more fundamental output and less THD than sinusoidal PWM technique. Key Words: Cascaded H bridge, Multilevel, Modulating wave, Space vector
Mitigation of Lower Order Harmonics with Filtered Svpwm In Multiphase Voltage...IJERA Editor
Multi-phase machines and drives is a topic of growing relevance in recent years, and it presents many challenging issues that still need further research. This is the case of multi-phase space vector pulse width modulation (SVPWM), which shows not only more space vectors than the standard three-phase case, but also new subspaces where the space vectors are mapped. In the digital implementation, multiphase reference voltages are sampled and fed into the digital modulator to produce gating signals at a constant clock rate f. This means a finite pulse-width resolution because the gating state transition can only occur at some specific time instants depending on frequency. This results in a deviation of produced phase voltages from the desired phase voltages, i.e., increasing harmonic distortion especially for a small modulation index signal. In the present paper a filtered space-vector pulse-width modulation (SVPWM) considering finite pulse-width resolution is proposed to produce a switching sequence with reduced baseband harmonics for multiphase voltage source inverters (VSI). This is achieved by incorporating a pseudo feedback loop regarding weighted voltage difference between desired and produced phase voltages.
The document compares different algorithms for detecting voltage sags and swells in power systems. It describes RMS voltage detection, peak voltage detection, and discrete Fourier transform (DFT) methods. RMS detection uses historical data so it can be slow for mitigation. Peak detection requires only single-phase values but DFT is best for steady signals and not fast transients. The paper proposes a novel real-time algorithm to rapidly detect voltage sags and compares it to existing methods.
Electrocardiogram Denoised Signal by Discrete Wavelet Transform and Continuou...CSCJournals
One of commonest problems in electrocardiogram (ECG) signal processing is denoising. In this paper a denoising technique based on discrete wavelet transform (DWT) has been developed. To evaluate proposed technique, we compare it to continuous wavelet transform (CWT). Performance evaluation uses parameters like mean square error (MSE) and signal to noise ratio (SNR) computations show that the proposed technique out performs the CWT.
Abstract-This paper presents the novel synchronous frame hysteresis controller for three phase Uninterruptible Power Supply (UPS)based on Z-Source Inverter (ZSI). The proposedsynchronous frame approach minimizes the hysteresis control time delay to onesixthof the fundamental period such that the dynamic response is significantly improved. The hysteresis band currentcontroller determines the switching signals, and the algorithm based onanextension of Synchronous Reference Frame(SRF) Theory (d-q-0) is used to determine thesuitable current reference signals. A filter is applied to further enhance the accuracy of steadystate tracking.Low total harmonic distortion has been achieved under heavilydistorted nonlinear load and unbalanced load.The ZSI provides agreat alternative with lower cost, higher reliability and higher efficiency.
This document presents the design of a high performance folded cascade OTA and sample and hold circuit. The OTA is designed to achieve 10-bit resolution while operating at a 28 MHz sampling frequency. Simulation results show the OTA achieves a high open loop gain of 72 dB and bandwidth of 112 MHz, with a phase margin of 73 degrees. A low resistance transmission gate switch is designed to reduce charge injection and clock feedthrough effects during sampling. The circuit is implemented in a 130 nm CMOS technology.
Synchronous Rectification for Forward Converters_SMappus_June 4 2010Steve Mappus
This document summarizes techniques for improving the efficiency of power converters by replacing diode rectifiers with synchronous rectifiers (SRs) using MOSFETs. SRs can reduce conduction losses by lowering the equivalent forward voltage drop compared to diodes. However, SRs introduce additional losses related to their body diode and switching operation that must be minimized through proper gate driving and timing. Integrating a Schottky diode with the SR MOSFET in a single package helps reduce body diode losses and reverse recovery effects. Optimizing the gate driving method and timing is critical for SR performance in forward converters.
This document proposes using continuous wavelet transform (CWT) with a complex Morlet wavelet to detect low frequency oscillations in a power system. CWT is applied to signals measured from a two-area four-machine power system model. The results extract the frequency and damping of inter-area oscillations, which closely match those obtained from eigenvalue analysis. This demonstrates CWT as an effective technique for identifying low frequency oscillations in power systems.
This document discusses a random zero vector distribution pulse width modulation (RZVDPWM) algorithm for direct torque control of an induction motor drive to reduce acoustic noise. The basic direct torque control algorithm results in torque, flux and current ripples that cause acoustic noise and incorrect speed estimations. While space vector PWM (SVPWM) improves performance, it can increase total harmonic distortion and acoustic noise. The proposed RZVDPWM algorithm distributes the zero state time between the two zero voltage vectors randomly in each sampling period. Simulation results show the proposed RZVDPWM algorithm reduces acoustic noise compared to SVPWM.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
This document presents a space vector based hybrid random PWM algorithm for direct torque controlled induction motor drives. The algorithm aims to achieve superior waveform quality with reduced harmonic distortion and acoustic noise. It uses three switching sequences - 0127, 012, and 721 - depending on the value of a factor μ, which varies the duration of the zero state vector V0. The harmonic analysis of these sequences is performed using notions of stator flux ripple. In each sampling interval, the sequence resulting in minimum current ripple is selected to reduce total harmonic distortion compared to standard space vector PWM. Randomizing the zero state time distribution also helps reduce dominant harmonics and acoustic noise.
Performance Analysis Of Induction Motor For Voltage Mode And Current Mode Con...IRJET Journal
This document discusses the performance analysis of an induction motor using voltage mode and current mode control. It compares hysteresis current control and space vector pulse width modulation (SVPWM). Hysteresis control directly limits current peaks but SVPWM provides higher voltage output and lower harmonic distortion. The document simulates an induction motor drive using SVPWM-based hysteresis current control in MATLAB. Key steps include Clark transformation to generate reference signals, switching between active and zero vectors to synthesize the reference signal, and using hysteresis control to generate PWM signals from current errors. Simulation results show the SVPWM controller provides good speed and current regulation for the induction motor.
Performance Improvement of Multi Level Inverter fed Vector Controlled Inducti...IJPEDS-IAES
In this paper, the analysis of space vector based multi level inverter (MLI) fed vector controlled induction motor drive for a low speed operation is presented. The performance of indirect field oriented controlled induction motor drive (IMD) is poor with two-level inverter for low speed operations (LSO). The reduction in performance and peak value of torque are mainly due to the non-linearity caused by stator voltage drop and inverter. Hence the performance factors of induction motor drive are analyzed with the multi level inverters under different operating conditions. In this approach, the steady state ripple content in the current and torque waveforms are reduced and that to ripple content of torque is reduced from 0.15 to 0.05 under steady state with five-level inverter. When there is a step change in the load torque, the momentary decrease in speed with five-level inverter is less when compared two and three-level inverters and the speed response reaches the reference value very quickly with five-level inverter during steady state and transient periods. So the overall performance of drive is improved with five- level inverter when compared to two-level and three- level inverters under low speed operations.
This document describes a simulation of a space vector PWM controller for a five-level voltage-fed inverter motor drive. It begins by introducing multilevel inverters and some of the challenges in controlling them, specifically the increased complexity with more levels. It then presents a new approach to implementing space vector PWM for a five-level inverter by treating it as a conventional two-level system, making the calculations simpler. The methodology and implementation are described, including estimating switching times. Simulation results are presented showing the current, voltage and THD waveforms both with and without an LC filter. It is concluded that the proposed 2D system approach allows for simple implementation of SVPWM for a five-level inverter using common D
This document discusses using artificial neural networks to solve the harmonics elimination problem in three-phase voltage-controlled inverters. It presents a new training algorithm for an ANN that does not use pre-computed switching angles from classical harmonic elimination methods. Instead, it trains the ANN by using the desired solution of the harmonic elimination equations, with the first harmonic equal to the modulation index and higher harmonics equal to zero. Theoretical analysis and simulation results show the high performance of using this ANN approach for generating optimal switching functions to control harmonics in inverters.
Space Vector Modulation with DC-Link Voltage Balancing Control for Three-Leve...IDES Editor
Modified space vector modulation (SVM) for
DC-link voltage balancing of three-level inverter is proposed
here. Effect of the DC-link capacitor voltage deviation on
inverter switching states is presented for three-level
inverter. Pulse pattern arrangements for proposed SVM
using degree of freedom available in choice of redundant
space vectors, sequencing of vectors, and splitting of duty
cycles of vector are best exploited. Seven-segment SVM
scheme and modified closed loop space vector DC-link
voltage balancing control schemes are implemented. The
effectiveness of proposed scheme is verified by simulations
and experimental verification on laboratory prototype.
This document presents space vector based generalized discontinuous pulse width modulation (GDPWM) algorithms for voltage source inverter (VSI) fed induction motor drives. The proposed algorithms aim to reduce the complexity of sector identification and angle calculation involved in conventional space vector PWM (CSVPWM). GDPWM uses the concept of imaginary switching times and variables like modulation phase angle δ and constant μ to generate modulation waveforms. Simulation results in MATLAB/Simulink show that the proposed GDPWM algorithms reduce current ripple compared to CSVPWM and different GDPWM sequences produce different total harmonic distortion levels in the motor current.
MODELLING AND IMPLEMENTATION OF AN IMPROVED DSVM SCHEME FOR PMSM DTCpaperpublications3
This document discusses modelling and implementing an improved direct self control (DSC) scheme for permanent magnet synchronous motors (PMSMs) using discrete space vector modulation (DSVM). It begins with an overview of field oriented control and direct torque control techniques for PMSMs. It then presents the PMSM model and basic direct torque control scheme. Issues with the basic DTC scheme like torque and flux ripples are discussed. The document reviews the existing DSVM DTC technique and proposes a new DSVM DTC scheme for PMSMs that takes motor speed and torque/flux errors into account. Comparisons of performance and switching losses between basic DTC and improved DSVM DTC are made through simulation and experiments.
This document summarizes a research paper that proposes modeling direct torque control of an inverter-fed induction motor as a hybrid system using discrete event modeling.
The paper first describes direct torque control and its issues with high torque ripple and variable switching frequency when using hysteresis comparators. It then presents a three step method: 1) Modeling direct torque control as a hybrid system with discrete voltage vector events and continuous flux and torque dynamics. 2) Abstracting the continuous dynamics as discrete events like flux entering/exiting regions. 3) Using supervisory control theory to control the induction motor.
The document focuses on modeling the inverter and induction motor as a discrete event system to address issues with direct torque control,
A Refined Space Vector PWM Signal Generation for Multilevel InvertersIDES Editor
A refined space vector modulation scheme for
multilevel inverters, using only the instantaneous sampled
reference signals is presented in this paper. The proposed
space vector pulse width modulation technique does not require
the sector information and look-up tables to select the
appropriate switching vectors. The inverter leg switching times
are directly obtained from the instantaneous sampled
reference signal amplitudes and centers the switching times
for the middle space vectors in a sampling time interval, as in
the case of conventional space vector pulse width modulation.
The simulation results are presented to a five-level inverter
system for dual-fed induction motor drive. The dual-fed
structure is realized by opening the neutral-point of the
conventional squirrel cage induction motor. The five-level
inversion is obtained by feeding the dual-fed induction motor
with four-level inverter from one end and two-level inverter
from the other end.
Optimal Coordination of DOCR for Radial Distribution Systems in Presence of TCSCIJPEDS-IAES
Protective relays coordination is the process of determining the exact relay
settings such that the relay closes to the fault would operates faster than other
relays. The operating time of each relay depends on two independent
variables called Pickup current (Ip) and Time Dial Setting (TDS). In this
paper, a PSO algorithm has been presented to determine the coordination of
Directional Over-Current Relays (DOCRs) in presence of multi-system
FACTS devises. From the simulation result and analysis, the impact of TCSC
location in the in 33-bus distribution system on Directional Over-Current
Relays has been observed on the optimal relays settings as well as the
effectiveness of the proposed algorithm in finding optimal coordination of
directional over-current relays.
Fast svm based 3 phase cascaded five level invertereSAT Journals
Abstract Introduction of nearest three vector algorithm is a major achievement in the area of space vector technology. Complexity and severe computations are still the drawbacks of SVM methods mainly for multilevel inverter applications. A fast SVM technique is introduced in this project which allows the calculation of switch time duration and the efficient determination of switching times based on the two level inverter scheme. SVM modulating waves are generated based on the two level system and then this modulating waves are compared with required number of carrier signals in order to generate the switching pulses for the inverter. Four triangular carrier signals are needed for a five level system in order to generate the switching pulses. Coordinates of the nearest three voltage vectors is not needed, so the complexity of the SVM technique can be reduced and it is the major advantage of the proposed technique compared with conventional SVM techniques used for multilevel inverters. A three phase five level cascaded H bridge topology is used here to verify the effectiveness of the proposed technique. MATLAB simulation and hardware implementation of the proposed system is done. From the analysis of both simulation and hardware it is clear that proposed SVM technique have more fundamental output and less THD than sinusoidal PWM technique. Key Words: Cascaded H bridge, Multilevel, Modulating wave, Space vector
Mitigation of Lower Order Harmonics with Filtered Svpwm In Multiphase Voltage...IJERA Editor
Multi-phase machines and drives is a topic of growing relevance in recent years, and it presents many challenging issues that still need further research. This is the case of multi-phase space vector pulse width modulation (SVPWM), which shows not only more space vectors than the standard three-phase case, but also new subspaces where the space vectors are mapped. In the digital implementation, multiphase reference voltages are sampled and fed into the digital modulator to produce gating signals at a constant clock rate f. This means a finite pulse-width resolution because the gating state transition can only occur at some specific time instants depending on frequency. This results in a deviation of produced phase voltages from the desired phase voltages, i.e., increasing harmonic distortion especially for a small modulation index signal. In the present paper a filtered space-vector pulse-width modulation (SVPWM) considering finite pulse-width resolution is proposed to produce a switching sequence with reduced baseband harmonics for multiphase voltage source inverters (VSI). This is achieved by incorporating a pseudo feedback loop regarding weighted voltage difference between desired and produced phase voltages.
The document compares different algorithms for detecting voltage sags and swells in power systems. It describes RMS voltage detection, peak voltage detection, and discrete Fourier transform (DFT) methods. RMS detection uses historical data so it can be slow for mitigation. Peak detection requires only single-phase values but DFT is best for steady signals and not fast transients. The paper proposes a novel real-time algorithm to rapidly detect voltage sags and compares it to existing methods.
Electrocardiogram Denoised Signal by Discrete Wavelet Transform and Continuou...CSCJournals
One of commonest problems in electrocardiogram (ECG) signal processing is denoising. In this paper a denoising technique based on discrete wavelet transform (DWT) has been developed. To evaluate proposed technique, we compare it to continuous wavelet transform (CWT). Performance evaluation uses parameters like mean square error (MSE) and signal to noise ratio (SNR) computations show that the proposed technique out performs the CWT.
Abstract-This paper presents the novel synchronous frame hysteresis controller for three phase Uninterruptible Power Supply (UPS)based on Z-Source Inverter (ZSI). The proposedsynchronous frame approach minimizes the hysteresis control time delay to onesixthof the fundamental period such that the dynamic response is significantly improved. The hysteresis band currentcontroller determines the switching signals, and the algorithm based onanextension of Synchronous Reference Frame(SRF) Theory (d-q-0) is used to determine thesuitable current reference signals. A filter is applied to further enhance the accuracy of steadystate tracking.Low total harmonic distortion has been achieved under heavilydistorted nonlinear load and unbalanced load.The ZSI provides agreat alternative with lower cost, higher reliability and higher efficiency.
This document presents the design of a high performance folded cascade OTA and sample and hold circuit. The OTA is designed to achieve 10-bit resolution while operating at a 28 MHz sampling frequency. Simulation results show the OTA achieves a high open loop gain of 72 dB and bandwidth of 112 MHz, with a phase margin of 73 degrees. A low resistance transmission gate switch is designed to reduce charge injection and clock feedthrough effects during sampling. The circuit is implemented in a 130 nm CMOS technology.
Synchronous Rectification for Forward Converters_SMappus_June 4 2010Steve Mappus
This document summarizes techniques for improving the efficiency of power converters by replacing diode rectifiers with synchronous rectifiers (SRs) using MOSFETs. SRs can reduce conduction losses by lowering the equivalent forward voltage drop compared to diodes. However, SRs introduce additional losses related to their body diode and switching operation that must be minimized through proper gate driving and timing. Integrating a Schottky diode with the SR MOSFET in a single package helps reduce body diode losses and reverse recovery effects. Optimizing the gate driving method and timing is critical for SR performance in forward converters.
This document proposes using continuous wavelet transform (CWT) with a complex Morlet wavelet to detect low frequency oscillations in a power system. CWT is applied to signals measured from a two-area four-machine power system model. The results extract the frequency and damping of inter-area oscillations, which closely match those obtained from eigenvalue analysis. This demonstrates CWT as an effective technique for identifying low frequency oscillations in power systems.
Similar to 3.[14 28]space vector based dual zero-vector random centered distribution pwm algorithm for direct torque control of induction motor drive for reduced acoustical noise
This document discusses a random zero vector distribution pulse width modulation (RZVDPWM) algorithm for direct torque control of an induction motor drive to reduce acoustic noise. The basic direct torque control algorithm results in torque, flux and current ripples that cause acoustic noise and incorrect speed estimations. While space vector PWM (SVPWM) improves performance, it can increase total harmonic distortion and acoustic noise. The proposed RZVDPWM algorithm distributes the zero state time between the two zero voltage vectors randomly in each sampling period. Simulation results show the proposed RZVDPWM algorithm reduces acoustic noise compared to SVPWM.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
This document presents a space vector based hybrid random PWM algorithm for direct torque controlled induction motor drives. The algorithm aims to achieve superior waveform quality with reduced harmonic distortion and acoustic noise. It uses three switching sequences - 0127, 012, and 721 - depending on the value of a factor μ, which varies the duration of the zero state vector V0. The harmonic analysis of these sequences is performed using notions of stator flux ripple. In each sampling interval, the sequence resulting in minimum current ripple is selected to reduce total harmonic distortion compared to standard space vector PWM. Randomizing the zero state time distribution also helps reduce dominant harmonics and acoustic noise.
Performance Analysis Of Induction Motor For Voltage Mode And Current Mode Con...IRJET Journal
This document discusses the performance analysis of an induction motor using voltage mode and current mode control. It compares hysteresis current control and space vector pulse width modulation (SVPWM). Hysteresis control directly limits current peaks but SVPWM provides higher voltage output and lower harmonic distortion. The document simulates an induction motor drive using SVPWM-based hysteresis current control in MATLAB. Key steps include Clark transformation to generate reference signals, switching between active and zero vectors to synthesize the reference signal, and using hysteresis control to generate PWM signals from current errors. Simulation results show the SVPWM controller provides good speed and current regulation for the induction motor.
Performance Improvement of Multi Level Inverter fed Vector Controlled Inducti...IJPEDS-IAES
In this paper, the analysis of space vector based multi level inverter (MLI) fed vector controlled induction motor drive for a low speed operation is presented. The performance of indirect field oriented controlled induction motor drive (IMD) is poor with two-level inverter for low speed operations (LSO). The reduction in performance and peak value of torque are mainly due to the non-linearity caused by stator voltage drop and inverter. Hence the performance factors of induction motor drive are analyzed with the multi level inverters under different operating conditions. In this approach, the steady state ripple content in the current and torque waveforms are reduced and that to ripple content of torque is reduced from 0.15 to 0.05 under steady state with five-level inverter. When there is a step change in the load torque, the momentary decrease in speed with five-level inverter is less when compared two and three-level inverters and the speed response reaches the reference value very quickly with five-level inverter during steady state and transient periods. So the overall performance of drive is improved with five- level inverter when compared to two-level and three- level inverters under low speed operations.
A Novel Direct Torque Control for Induction Machine Drive System with Low Tor...IAES-IJPEDS
This document describes a novel direct torque control method for induction machine drives using space vector modulation (DTC-SVM) to reduce torque and flux ripples. Simulation results show the proposed DTC-SVM control achieves lower ripples compared to the conventional DTC method. The DTC-SVM control strategy is designed and simulated using Matlab/Simulink and implemented on an FPGA using Xilinx System Generator. Simulation results verify the DTC-SVM control is effective at minimizing torque and flux ripples for induction machine drives.
Implementation of d space controlled dpwm basedeSAT Journals
Abstract The paper presents dSPACE controlled Induction motor drive fed through Discontinuous pulse width modulation (DPWM) algorithm based voltage source inverter. Two important performance measuring factors harmonic distortion in line current and dc bus utilization of the inverter can be improved with Discontinuous PWM approach in comparison with the popular conventional space vector (CSVPWM) approach; the paper contemplates on the implementation of DPWM algorithm for pulse generation which in turn are fed to intelligent power module that feeds the motor drive through DS1104 PPC603e / 250 MHz control desk. The results conclude the successful implementation of dSPACE Controlled induction motor drive. To validate the proposed work, numerical simulation including the experimental results is presented. Keywords:-DPWM, dSPACE, RTI
Total Harmonic Distortion of Dodecagonal Space Vector ModulationIJPEDS-IAES
Space vector modulation technique is one of the best PWM techniques which have been implemented to the Multilevel inverter circuit to get the purely sinusoidal cuurent. This is a important algorithm which is implemented in open wind induction motor. This type of I.M has great impact on Electric Drive system. SVM is nothing but the technique of switching algorithm. The Hexagonal space vector modulation has been implemented before, but elimination of higher order harmonics is not possible. Torque pulsation arises. Speed control of Induction motor was not smooth. So Dodecagonal (12) structure developed. A 12 side polygonal space vector structure is meant for eliminating (6n±1) harmonics in the phase current waveform throughout the modulating range. A high resolution of PWM technique is proposed involving multiple 12 sided polygonal (Dodecagonal) structure that can generate highly sinusoidal voltage at a reduced switching frequency. In this paper different values of frequencies have been taken for harmonic analysis. SVM method features a higher level of dc-bus voltage utilization compared to the conventional PWM.
This document presents a comparative study of five-level and seven-level diode-clamped inverters controlled by space vector pulse width modulation (SVPWM). MATLAB/SIMULINK models of the two inverter topologies were developed. SVPWM control algorithms based on symmetrical sequence were used for each inverter. Both inverters were simulated driving an induction motor. The results showed that the seven-level inverter produced less harmonic distortion and torque fluctuations in the motor, while the five-level inverter had lower commutation losses. The seven-level inverter provided better motor dynamic response.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Simulation Investigation of SPWM, THIPWM and SVPWM Techniques for Three Phase...IJPEDS-IAES
This document summarizes and compares three pulse width modulation techniques - sinusoidal PWM (SPWM), third harmonic injection PWM (THIPWM), and space vector PWM (SVPWM) - for a three-phase voltage source inverter. SPWM is the simplest technique but has drawbacks like higher total harmonic distortion and lower switching frequency. THIPWM provides better THD than SPWM. SVPWM shows lower THD than both SPWM and THIPWM, especially in overmodulation regions and at high frequencies. The document presents the theoretical principles, simulation models, and results of the three techniques, showing that SVPWM achieves the best performance and meets current harmonic standards.
Implementation of Space Vector PWM for Hybrid DSTATCOMIRJET Journal
This document discusses the implementation of space vector pulse width modulation (SVPWM) for a hybrid distribution static compensator (DSTATCOM). SVPWM is considered superior to other PWM techniques for DSTATCOM as it allows for better utilization of the DC bus voltage. The paper proposes a DSTATCOM topology using a three-phase voltage source inverter with an LCL filter. It describes the SVPWM technique which aims to generate the desired output voltage vector from the inverter's six active state vectors and two null state vectors. Simulation results show that SVPWM improves current compensation and reduces harmonic distortion compared to an uncompensated system.
The document discusses pulse width modulation (PWM) variable speed drives that are increasingly used in industrial applications. It describes how PWM is used to generate variable voltage and frequency for AC drives from a three-phase voltage source inverter. Space vector PWM (SVPWM) is highlighted as it provides superior harmonic quality and larger modulation range compared to sinusoidal PWM. SVPWM represents the inverter states as voltage space vectors to calculate duty cycles for adjacent vectors and zero vectors to synthesize the desired output voltage vector. The document outlines the theory of SVPWM and compares different sequencing methods. It also discusses simulations and advantages of PWM including proportional average value, fast switching, noise resistance and less heat.
Analysis of SVPWM for Inverter fed DTC of Induction motor DriveIJSRED
This document analyzes and compares space vector pulse width modulation (SVPWM) and sinusoidal pulse width modulation (SPWM) for controlling an induction motor drive using direct torque control (DTC). It finds that SVPWM reduces harmonic content in voltages and currents compared to SPWM, allowing for higher output voltage. The document simulates an induction motor drive using SVPWM and proportional-integral control in MATLAB/Simulink. The results show SVPWM provides improved torque waveform quality over SPWM and DTC with a PI controller alone.
RANDOM PULSEWIDTH MODULATION TECHNIQUE FOR A 4-LEVEL INVERTERIAEME Publication
Random Pulse Width Modulation (RPWM) technique for a 4-level inverter in open-end winding induction motor configuration is proposed i n this paper. Reference voltage space vector is randomly sampled and it is realized in average sens e by switching its three nearest vectors. Switching frequency is randomly varied within the bounds to get randomly s paced samples. The method requires no sector identification. The refer encephasor is converted into a vector lying in the basic 2-level inverter to calculate switching time vectors. The proposed scheme is implemented and experimental results are presented for a dual inverter fed 4-level open-end winding induction motor drive using DSP platform, TMS 320LF2407A.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
OPTIMAL TORQUE RIPPLE CONTROL OF ASYNCHRONOUS DRIVE USING INTELLIGENT CONTROL...elelijjournal
This document summarizes a research paper on optimizing torque ripple in an asynchronous drive using intelligent controllers. It describes using a hybrid controller combining PI and fuzzy logic control with direct torque control and space vector modulation of a three-level cascaded inverter to power an induction motor drive. Simulation results showed the hybrid controller approach minimized torque ripple compared to using just PI or fuzzy logic control alone under no-load and loaded conditions. The optimized torque control method provides benefits for general purpose induction motor applications.
1. The document presents space vector modulation for two leg inverters. Space vector modulation treats the inverter as a single unit and provides better voltage utilization compared to sinusoidal pulse width modulation.
2. Space vector modulation represents the reference voltage as a combination of four switching vectors and determines the switching times of each transistor based on the location of the reference vector in the selected sector.
3. Simulation results show that space vector modulation generates less output voltage harmonics than sinusoidal pulse width modulation for two leg inverters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Tactical Chaos based PWM Technique for Distortion Restraint and Power Spect...IJPEDS-IAES
The pulse width modulated voltage source inverters (PWM-VSI) dominate in the modern industrial environment. The conventional PWM methods are designed to have higher fundamental voltage, easy filtering and reduced total harmonic distortion (THD). There are number of clustered harmonics around the multiples of switching frequency in the output of conventional sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) inverters. This is due to their fixed switching frequency while the variable switching frequency makes the filtering very complex. Random carrier PWM (RCPWM) methods are the host of PWM methods, which use randomized carrier frequency and result in a harmonic profile with well distributed harmonic power (no harmonic possesses significant magnitude and hence no filtering is required). This paper proposes a chaos-based PWM (CPWM) strategy, which utilizes a chaotically changing switching frequency to spread the harmonics continuously to a wideband and to reduce the peak harmonics to a great extent. This can be an effective way to suppress the current harmonics and torque ripple in induction motor drives. The proposed CPWM scheme is simulated using MATLAB / SIMULINK software and implemented in three phase voltage source inverter (VSI) using field programmable gate array (FPGA).
Similar to 3.[14 28]space vector based dual zero-vector random centered distribution pwm algorithm for direct torque control of induction motor drive for reduced acoustical noise (20)
Abnormalities of hormones and inflammatory cytokines in women affected with p...Alexander Decker
Women with polycystic ovary syndrome (PCOS) have elevated levels of hormones like luteinizing hormone and testosterone, as well as higher levels of insulin and insulin resistance compared to healthy women. They also have increased levels of inflammatory markers like C-reactive protein, interleukin-6, and leptin. This study found these abnormalities in the hormones and inflammatory cytokines of women with PCOS ages 23-40, indicating that hormone imbalances associated with insulin resistance and elevated inflammatory markers may worsen infertility in women with PCOS.
A usability evaluation framework for b2 c e commerce websitesAlexander Decker
This document presents a framework for evaluating the usability of B2C e-commerce websites. It involves user testing methods like usability testing and interviews to identify usability problems in areas like navigation, design, purchasing processes, and customer service. The framework specifies goals for the evaluation, determines which website aspects to evaluate, and identifies target users. It then describes collecting data through user testing and analyzing the results to identify usability problems and suggest improvements.
A universal model for managing the marketing executives in nigerian banksAlexander Decker
This document discusses a study that aimed to synthesize motivation theories into a universal model for managing marketing executives in Nigerian banks. The study was guided by Maslow and McGregor's theories. A sample of 303 marketing executives was used. The results showed that managers will be most effective at motivating marketing executives if they consider individual needs and create challenging but attainable goals. The emerged model suggests managers should provide job satisfaction by tailoring assignments to abilities and monitoring performance with feedback. This addresses confusion faced by Nigerian bank managers in determining effective motivation strategies.
A unique common fixed point theorems in generalized dAlexander Decker
This document presents definitions and properties related to generalized D*-metric spaces and establishes some common fixed point theorems for contractive type mappings in these spaces. It begins by introducing D*-metric spaces and generalized D*-metric spaces, defines concepts like convergence and Cauchy sequences. It presents lemmas showing the uniqueness of limits in these spaces and the equivalence of different definitions of convergence. The goal of the paper is then stated as obtaining a unique common fixed point theorem for generalized D*-metric spaces.
A trends of salmonella and antibiotic resistanceAlexander Decker
This document provides a review of trends in Salmonella and antibiotic resistance. It begins with an introduction to Salmonella as a facultative anaerobe that causes nontyphoidal salmonellosis. The emergence of antimicrobial-resistant Salmonella is then discussed. The document proceeds to cover the historical perspective and classification of Salmonella, definitions of antimicrobials and antibiotic resistance, and mechanisms of antibiotic resistance in Salmonella including modification or destruction of antimicrobial agents, efflux pumps, modification of antibiotic targets, and decreased membrane permeability. Specific resistance mechanisms are discussed for several classes of antimicrobials.
A transformational generative approach towards understanding al-istifhamAlexander Decker
This document discusses a transformational-generative approach to understanding Al-Istifham, which refers to interrogative sentences in Arabic. It begins with an introduction to the origin and development of Arabic grammar. The paper then explains the theoretical framework of transformational-generative grammar that is used. Basic linguistic concepts and terms related to Arabic grammar are defined. The document analyzes how interrogative sentences in Arabic can be derived and transformed via tools from transformational-generative grammar, categorizing Al-Istifham into linguistic and literary questions.
A time series analysis of the determinants of savings in namibiaAlexander Decker
This document summarizes a study on the determinants of savings in Namibia from 1991 to 2012. It reviews previous literature on savings determinants in developing countries. The study uses time series analysis including unit root tests, cointegration, and error correction models to analyze the relationship between savings and variables like income, inflation, population growth, deposit rates, and financial deepening in Namibia. The results found inflation and income have a positive impact on savings, while population growth negatively impacts savings. Deposit rates and financial deepening were found to have no significant impact. The study reinforces previous work and emphasizes the importance of improving income levels to achieve higher savings rates in Namibia.
A therapy for physical and mental fitness of school childrenAlexander Decker
This document summarizes a study on the importance of exercise in maintaining physical and mental fitness for school children. It discusses how physical and mental fitness are developed through participation in regular physical exercises and cannot be achieved solely through classroom learning. The document outlines different types and components of fitness and argues that developing fitness should be a key objective of education systems. It recommends that schools ensure pupils engage in graded physical activities and exercises to support their overall development.
A theory of efficiency for managing the marketing executives in nigerian banksAlexander Decker
This document summarizes a study examining efficiency in managing marketing executives in Nigerian banks. The study was examined through the lenses of Kaizen theory (continuous improvement) and efficiency theory. A survey of 303 marketing executives from Nigerian banks found that management plays a key role in identifying and implementing efficiency improvements. The document recommends adopting a "3H grand strategy" to improve the heads, hearts, and hands of management and marketing executives by enhancing their knowledge, attitudes, and tools.
This document discusses evaluating the link budget for effective 900MHz GSM communication. It describes the basic parameters needed for a high-level link budget calculation, including transmitter power, antenna gains, path loss, and propagation models. Common propagation models for 900MHz that are described include Okumura model for urban areas and Hata model for urban, suburban, and open areas. Rain attenuation is also incorporated using the updated ITU model to improve communication during rainfall.
A synthetic review of contraceptive supplies in punjabAlexander Decker
This document discusses contraceptive use in Punjab, Pakistan. It begins by providing background on the benefits of family planning and contraceptive use for maternal and child health. It then analyzes contraceptive commodity data from Punjab, finding that use is still low despite efforts to improve access. The document concludes by emphasizing the need for strategies to bridge gaps and meet the unmet need for effective and affordable contraceptive methods and supplies in Punjab in order to improve health outcomes.
A synthesis of taylor’s and fayol’s management approaches for managing market...Alexander Decker
1) The document discusses synthesizing Taylor's scientific management approach and Fayol's process management approach to identify an effective way to manage marketing executives in Nigerian banks.
2) It reviews Taylor's emphasis on efficiency and breaking tasks into small parts, and Fayol's focus on developing general management principles.
3) The study administered a survey to 303 marketing executives in Nigerian banks to test if combining elements of Taylor and Fayol's approaches would help manage their performance through clear roles, accountability, and motivation. Statistical analysis supported combining the two approaches.
A survey paper on sequence pattern mining with incrementalAlexander Decker
This document summarizes four algorithms for sequential pattern mining: GSP, ISM, FreeSpan, and PrefixSpan. GSP is an Apriori-based algorithm that incorporates time constraints. ISM extends SPADE to incrementally update patterns after database changes. FreeSpan uses frequent items to recursively project databases and grow subsequences. PrefixSpan also uses projection but claims to not require candidate generation. It recursively projects databases based on short prefix patterns. The document concludes by stating the goal was to find an efficient scheme for extracting sequential patterns from transactional datasets.
A survey on live virtual machine migrations and its techniquesAlexander Decker
This document summarizes several techniques for live virtual machine migration in cloud computing. It discusses works that have proposed affinity-aware migration models to improve resource utilization, energy efficient migration approaches using storage migration and live VM migration, and a dynamic consolidation technique using migration control to avoid unnecessary migrations. The document also summarizes works that have designed methods to minimize migration downtime and network traffic, proposed a resource reservation framework for efficient migration of multiple VMs, and addressed real-time issues in live migration. Finally, it provides a table summarizing the techniques, tools used, and potential future work or gaps identified for each discussed work.
A survey on data mining and analysis in hadoop and mongo dbAlexander Decker
This document discusses data mining of big data using Hadoop and MongoDB. It provides an overview of Hadoop and MongoDB and their uses in big data analysis. Specifically, it proposes using Hadoop for distributed processing and MongoDB for data storage and input. The document reviews several related works that discuss big data analysis using these tools, as well as their capabilities for scalable data storage and mining. It aims to improve computational time and fault tolerance for big data analysis by mining data stored in Hadoop using MongoDB and MapReduce.
1. The document discusses several challenges for integrating media with cloud computing including media content convergence, scalability and expandability, finding appropriate applications, and reliability.
2. Media content convergence challenges include dealing with the heterogeneity of media types, services, networks, devices, and quality of service requirements as well as integrating technologies used by media providers and consumers.
3. Scalability and expandability challenges involve adapting to the increasing volume of media content and being able to support new media formats and outlets over time.
This document surveys trust architectures that leverage provenance in wireless sensor networks. It begins with background on provenance, which refers to the documented history or derivation of data. Provenance can be used to assess trust by providing metadata about how data was processed. The document then discusses challenges for using provenance to establish trust in wireless sensor networks, which have constraints on energy and computation. Finally, it provides background on trust, which is the subjective probability that a node will behave dependably. Trust architectures need to be lightweight to account for the constraints of wireless sensor networks.
This document discusses private equity investments in Kenya. It provides background on private equity and discusses trends in various regions. The objectives of the study discussed are to establish the extent of private equity adoption in Kenya, identify common forms of private equity utilized, and determine typical exit strategies. Private equity can involve venture capital, leveraged buyouts, or mezzanine financing. Exits allow recycling of capital into new opportunities. The document provides context on private equity globally and in developing markets like Africa to frame the goals of the study.
This document discusses a study that analyzes the financial health of the Indian logistics industry from 2005-2012 using Altman's Z-score model. The study finds that the average Z-score for selected logistics firms was in the healthy to very healthy range during the study period. The average Z-score increased from 2006 to 2010 when the Indian economy was hit by the global recession, indicating the overall performance of the Indian logistics industry was good. The document reviews previous literature on measuring financial performance and distress using ratios and Z-scores, and outlines the objectives and methodology used in the current study.
Adani Group Requests For Additional Land For Its Dharavi Redevelopment Projec...Adani case
It will bring about growth and development not only in Maharashtra but also in our country as a whole, which will experience prosperity. The project will also give the Adani Group an opportunity to rise above the controversies that have been ongoing since the Adani CBI Investigation.
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NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi_compressed.pdfKhaled Al Awadi
Greetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USAGreetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USAGreetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USAGreetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USAGreetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USAGreetings,
Hawk Energy is pleased to present you with the latest energy news
NewBase 20 June 2024 Energy News issue - 1731 by Khaled Al Awadi
Regards.
Founder & S.Editor - NewBase Energy
Khaled M Al Awadi, Energy Consultant
MS & BS Mechanical Engineering (HON), USA
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3.[14 28]space vector based dual zero-vector random centered distribution pwm algorithm for direct torque control of induction motor drive for reduced acoustical noise
1. Control Theory and Informatics www.iiste.org
ISSN 2224-5774 (print) ISSN 2225-0492 (online)
Vol 1, No.2, 2011
Space Vector Based Dual Zero-Vector Random Centered
Distribution Pwm Algorithm for Direct Torque Control of
Induction Motor Drive For Reduced Acoustical Noise
P. Nagasekhara Reddy
Mahatma Gandhi Institute of Technology
Gandipet, Hyderabad, Andhra Pradesh, India, pnsreddy04@gmail.com
J. Amarnath
Jawaharlal Nehru technological University
Kukatpally, Hyderabad, Andhra Pradesh, India, amarnathjinka@rediffmail.com
P. Linga Reddy
K.L. University
Guntur, Andhra Pradesh, India,lingareddy.klu@gmail.com
Abstract
The direct torque control (DTC) technique has been recognized as the viable solution to achieve precise
and quick torque response but it suffers from few drawbacks such as high ripple in torque, flux and stator
current resulting in increased vibrations and acoustic noise. The conventional SVPWM algorithm gives
good performance for control of induction motor drive, but it also produces considerable acoustical noise
resulting in increased total harmonics distortion. The deterministic pulse width-modulation (PWM) method
adopted in induction-motor drives causes Acoustical noise due to the switching frequency. This paper
presents a novel dual zero-vector random centered distribution PWM algorithm for direct torque controlled
induction motor drive. The proposed PWM algorithm uses two zero voltage vectors. When the operating
modulation index is less than the critical modulation index, the proposed PWM algorithm uses V0 (000) as
zero voltage vector. Otherwise, when the operating modulation index is greater than the critical modulation
index, the proposed PWM algorithm uses V7 (111) as zero voltage vector. To verify the proposed PWM
algorithm, a numerical simulation studies have been carried out and results are presented and compared
with classical SVPWM algorithm. The simulation results confirm the effectiveness of the proposed
DZRCDPWM algorithm for the considered drive.
Key words: DTC, DZRCDPWM, RPWM, SVPWM, Acoustic noise.
1. Introduction
In recent years, the research has been focused to find out different solutions for the induction
motor control having the features of precise and quick torque response and reduction of the
complexity of field oriented algorithms. The invention of field oriented control (FOC) algorithm
by F. Blaschke provides high-performance but the complexity involved is more due to the
reference frame transformations. To overcome the drawbacks of FOC, a new control strategy
renowned as direct torque control (DTC) was developed by Takahashi [1]-[2]. A detailed
comparison between FOC and DTC has given in [3].Though conventional DTC (CDTC) is simple
and easy to implement; it generates substantial steady state ripples in torque and current. To reduce
the steady state ripple and to get the constant switching frequency, several pulse width modulation
(PWM) techniques were proposed to DTC algorithm. A detailed survey of the various PWM
algorithms is given in [4]. Recently, random PWM techniques are being investigated by various
researchers, and which include driving at a low switching frequency to reduce the switching noise.
Random PWM is classified into three categories as random switching frequency PWM [5]–[6],
random pulse position PWM [7], and hybrid random PWM [8], [9]. Even though the random pulse
position PWM is operated at a fixed frequency, the random pulse position has a similar effect as if
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the switching frequency is changed. Random pulse position PWM schemes are classified into
random lead-lag (RLL) PWM [10], random centered distribution PWM (RCD-PWM), random
zero vector distribution PWM [11], and separately randomized pulse position PWM [12].
In this paper, we propose the dual-zero-vector random centered distribution (DZRCD)-PWM
algorithm which can obtain the randomization effect on the spectra in the entire area of modulation
index with classical SVPWM algorithm approach. The results of this drive are compared with that
of the conventional DTC and classical SVPWM based induction motor drive.
2. Space Vector PWM Algorithm
In recent years voltage source inverter (VSI) is widely used to generate variable voltage, variable
frequency, 3-phase ac required for variable speed ac drives. The ac voltage is defined by two
characteristics, namely amplitude and frequency. Hence, it is essential to work out an algorithm
that permits control over both of these quantities. Pulse width modulation (PWM) controls the
average output voltage over a sufficiently small period called sampling period, by producing
pulses of variable duty-cycle. The approach to PWM that is described in this paper is based on the
space vector representation of the voltage in the stationary reference frame. The set of balanced
three-phase voltages can be represented in the stationary reference frame by a space vector of
constant magnitude, equal to the amplitude of the voltages, and rotating with angular speed ω=2πf.
The space vector locations for the switching states may be evaluated using (4). Then, all the
possible switching states of an inverter may be depicted as voltage space vectors as shown in Fig
1.
2 4
2
Vao Vbo e
j j
Vs 3
Vco e 3
(4)
3
The active voltage vectors or active states can be represented as
2 j ( k 1)
Vk Vdce 3
where k 1,2,....,6 (5)
3
A combination of switching states can be utilized, while maintaining the volt-second balance to
generate a given sample in an average sense during a sub-cycle. The reference voltage space vector
(Vref) represents the desired value of the fundamental components for the output phase voltages. In
the space vector approach, (Vref) can be constructed in an average manner. The reference voltage
vector (Vref) is sampled at equal intervals of time, Ts referred to as sampling time period. The
possible voltage vectors that can be produced by the inverter are applied for different time
durations within a sampling time period such that the average vector produced over the Ts is equal
to (Vref), both in magnitude and angle.
It has been established that the vectors to be used to generate any sample are the zero voltage
vectors and the two active voltage vectors forming the boundary of the sector in which the sample
lies. As all six sectors are symmetrical, the discussion is limited to the first sector only. For the
required reference voltage vector, the active and zero voltage vectors times can be calculated as in
(1) - (3).
2 3
T1 M i sin(60o )Ts (6)
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2 3
T2 M i sin( )Ts (7)
Tz Ts T1 T2 (8)
Where Mi - the modulation index and defined as M i Vref 2Vdc . In the SVPWM algorithm, the
total zero voltage vector time is equally divided between V0 and V7 and distributed symmetrically
at the start and end of the each sampling time period. As the classical SVPWM algorithm gives the
switching times in a deterministic manner, it is also known as deterministic SVPWM algorithm.
In SVPWM algorithm, during steady state operation notable torque, flux and current pulsations
occur which are reflected in speed estimation and in increased acoustical noise.
3. Proposed VDRPWM Algorithms
In RCDPWM algorithm the pulses are mutually center-aligned as in space vector modulation,
but the common pulse center is displaced by the amount αcT from the middle of the period. The
parameter αc is varied randomly within a band limited by the maximum duty cycle. The RCD-
PWM is a type of random PWM in which the center of a two- or three-phase pulse position is
placed randomly in the modulation interval. Compared with RLL PWM, this method has better
spreading effects of the voltage and noise spectra [11]. However, the RCDPWM algorithm did not
give good performance at higher modulation indices. Hence to get good performance at all
modulation indices, this paper presents a novel dual zero-vector random centered distribution
PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive. The proposed
algorithm uses two-phase modulation with two zero voltage vectors. Among the two possible zero
voltage vectors, any one is selected based on the operating modulation index. In the proposed
PWM algorithm, the zero voltage vector V0 (000) is used in the lower modulation indices and the
zero voltage vector V7 (111) is used in higher modulation indices. If V0(000) is selected as the zero
voltage vector, then the degree of freedom for the pulses is calculated by the zero state time
duration T0 and if V7(111) is selected as the zero voltage vector, the active voltage vector time
duration T1. Thus, if T0 is equal to T1, the degree of freedom for the pulse position is equal
irrespective of the selection of the zero voltage vectors. Therefore, a critical modulation index (Mc)
can be introduced as a reference for the selection of zero voltage vectors. The Mc can be obtained
by selecting Mi such that T0 and T1 are equal. For odd sectors, the Mc,odd is expressed as given in
(9).
1 (9)
Mc, odd
4 3 2 3
sin(60o ) sin
For even sectors, the Mc,even is expressed as given in (10).
1 (10)
M c, even
2 3 4 3
sin(60o ) sin
The variation of critical modulation index according to the angle of the reference voltage vector
can be plotted by using (9) and (10) as shown in Fig. 2.
The variation of Mc is limited to one. From Fig. 2, it can be observed that the minimum value of
Mc is 0.5236. In the proposed DZRCDPWM algorithm, the operating modulation index (M i) is
compared with the Mc in every sampling interval. The V7 (111) is selected as zero voltage vector if
Mi is greater than the Mc, otherwise, V0 (000) is selected as zero voltage vector if Mi is less than
the Mc. According to the selected value of zero voltage vectors, the gating pulses will be
generated.
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4. Proposed DZRCDPWM algorithm based induction motor drive
The reference voltage space vector can be constructed in many ways. But, to reduce the
complexity of the algorithm, in this thesis, the required reference voltage vector, to control the
torque and flux cycle-by-cycle basis is constructed by using the errors between the reference d-axis
and q-axis stator fluxes and d-axis and q-axis estimated stator fluxes sampled from the previous
cycle. The block diagram of the proposed novel dual zero random centered algorithm based DTC
is as shown in Fig 3.
In the proposed method, the position of the reference stator flux vector s * is derived by the
addition of slip speed and actual rotor speed. The actual synchronous speed of the stator flux
vector s is calculated from the adaptive motor model. After each sampling interval, actual stator
flux vector s is corrected by the error and it tries to attain the reference flux space vector s * .
The reference values of the d-axis and q- axis stator fluxes and actual values of the d-axis and q-
axis stator fluxes are compared in the reference voltage vector calculator block and hence the
errors in the d-axis and q-axis stator flux vectors are obtained as in (11)-(12).
ds ds * ds (11)
qs qs* qs (12)
The knowledge of flux error and stator ohmic drop allows the determination of appropriate
reference voltage space vectors as given in (13)-(14).
ds (13)
V* R i
ds s ds
Ts
qs (14)
*
V qs R s i qs
Ts
These derived d-q components of the reference voltage vectors are passed to the PWM block. In
PWM block, these two-phase voltages are then converted into three-phase voltages. Later, the
switching times are calculated as explained in the earlier sections for DZRCDWM control.
5. Simulation Results and Discussion
To verify the proposed conventional DZRCDPWM based induction motor drive, simulation
studies have been carried out on direct torque controlled induction motor drive by using
MATLAB/SIMULINK. For the simulation analysis, the reference flux is considered as 1wb and
starting torque is limited to 15 N-m. The induction motor used in this case study is a 3-phase, 4-
pole, 1.5 kW, 1440 rpm and having the parameters as Rs = 7.83Ω, Rr = 7.55 Ω, Ls = 0.4751H, Lr
= 0.4751H, Lm = 0.4535 H and J = 0.06 Kg.m2. The steady state results of conventional DTC and
SVPWM algorithm based DTC are shown in Fig.4-Fig.5. From the results it is clear that SVPWM
algorithm based drive gives superior performance and reduced harmonic distortion when
compared with conventional DTC, but it gives considerable acoustical noise due to large
amplitudes of dominating harmonics around switching frequency (5 kHz). Hence, to minimize the
acoustical noise and THD of the drive, a novel DZRCDPWM algorithm is implemented. The
simulation results of novel DZRCDRPWM algorithm based induction motor drive are shown in
Fig. 6- Fig.11, from which it can be observed that the novel DZRCDPWM algorithm gives
reduced acoustical noise when compared with a classical SVPWM algorithm based drive.
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6. Conclusions
To overcome the drawbacks of classical SVPWM algorithm, a novel DZRCDPWM algorithm is
presented in this paper. The proposed algorithm uses two-phase PWM algorithms with dual zero
voltage vectors. According to the operating modulation index, suitable zero voltage vectors is
selected to randomize the pulse pattern. From the simulation results, it can be observed that the
proposed DZRCDPWM algorithm gives reduced acoustical noise as the dominating harmonics
amplitude is less. Thus, the simulation results confirm the effectiveness of the proposed PWM
algorithm.
References
1. Isao Takahashi, Toshihiko Noguchi, “A new quick response and high-efficiency control trategy
of an induction motor”, IEEE Trans Ind Appl, vol.IA-22, No.5, pp. 820-827, Sep/Oct, 1986.
[2] James N. Nash, “Direct Torque Control, Induction Motor Vector Control Without an
Encoder”, IEEE Trans. Ind. Appl., vol 33, pp. 333-341, Mar/Apr 1997.
[3] Domenico Casadei, Francesco Profumo, Giovanni Serra, and Angelo Tani, “FOC and DTC:
Two Viable Schemes for Induction Motors Torque Control” IEEE Trans. Power Electron., vol. 17,
no.5, Sep, 2002, pp. 779-787.
[4] Joachim Holtz, “Pulsewidth modulation – A survey” IEEE Trans. Ind. Electron.., vol. 39, no.
5, Dec 1992, pp. 410-420.
[5] J.-Y. Chai, Y.-H. Ho, Y.-C. Chang, and C.-M. Liaw, “On acoustic-noise-reduction control
using random switching technique for switch-mode rectifiers in PMSM drive,” IEEE Trans. Ind.
Electron., vol. 55, no. 3, pp. 1295–1309, Mar. 2008.
[6] T. G. Habetler and D. M. Divian, “Acoustic noise reduction in sinusoidal PWM drives using a
randomly modulated carrier,” IEEE Trans. Power Electron., vol. 6, no. 3, pp. 356–363, Jul. 1991.
[7] Y. G. Jung, S. H. Na, and Y. C. Lim, “A new random PWM (SRP-PWM) technique for
decreasing acoustic noise radiated from v/f controlled motor drives,” in Proc. IEEE IECON,
2004, pp. 832–837.
[8] V. Blasko,M.M. Bech, F. Blaabjerg, and K. Pedersen, “A new hybrid ran-dom pulse width
modulator for industrial drives,” in Proc. IEEE APEC,2000, pp. 932–938.
[9] K. S. Kim, Y. G. Jung, and Y. C. Lim, “A new hybrid random PWM scheme,” IEEE Trans.
Power Electron., vol. 24, no. 1, pp. 192–200,Jan. 2009.
[10] R. L. Kirlin, S. Kwok, S. Legowski, and A. M. Trzynadlowski, “Power spectra of a PWM
inverter with randomized pulse position,” IEEE Trans.Power Electron., vol. 9, no. 5, pp. 463–471,
Sep. 1994.
[11] M. M. Bech, J. K. Pedersen, and F. Blaabjerg, “Random modulation tech- niques with fixed
switching frequency for three-phase power converters,” IEEE Trans. Power Electron., vol. 15, no.
4, pp. 753–761, Jul. 2000.
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[12] Y. G. Jung, S. H. Na, Y. C. Lim, and S. H. Yang, “Reduction of audible switching noise in
induction motor drives using random position space vector PWM,” Proc. Inst. Elect. Eng.—Elect.
Power Appl., vol. 149, no. 3, pp. 195–200, May 2002.
Authors Profile
P. Nagasekhar Reddy received his M.Tech degree from Jawaharlal Nehru technological University,
Hyderabad, India in 1976. He is presently working as Sr. Assistant Professor, MGIT, Hyderabad. Also, he is
pursuing his Ph.D in Jawaharlal Nehru technological University, Hyderabad, India. His research interests
include PWM techniques and control of electrical drives.
Dr. P. Linga Reddy received his Ph.D degree from Indian Institute of Technology, Delhi in 1978. He is
presently working as Professor at K.L. University, Guntur, India. He is having more than 45 years experience
in teaching. He published more than 15 papers in various national and international journals and conferences.
His research interests include control systems and control of electrical drives.
Dr. J. Amarnath graduated from Osmania University in the year 1982, M.E from Andhra University in the
year 1984 and Ph.D from J.N.T.University, Hyderabad in the year 2001. He is presently Professor and Head of
the Electrical and Electronics Engineering Department, JNTU College of Engineering, Hyderabad and also he
is the Chairman, Board of studies in Electrical and Electronics Engineering, JNTU College of Engineering,
Hyderabad. He presented more than 100 research papers in various national and international conferences and
journals.
His research areas include Gas Insulated Substations, High Voltage Engineering, Power Systems and Electrical
Drives.
V3 V2
(010) II (110)
III T Vref I
2 Motor
V7 (111) V
Model1
V4 (011)
V0 T (100)
(000) 1
VI
IV
V
V5 V6
(001) (101)
Fig 1. Voltage space vectors produced by an inverter
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Fig. 2 Variation of Mc with α
Vdc
Te sl e V
e ds
PI PI
+
Reference
P
Ref
+ W
_ Voltage
speed Te r + Vector
M
+ s
*
Calculator
*
_ V qs
Speed
s Vds, Vqs
Calculation
Torque, speed
and flux
Estimation
3
2
IM
Fig. 3 Block diagram of proposed novel DZRCD based Direct Torque Control
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Fig. 4 Starting transients of conventional DTC
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Fig. 5 Starting transients of classical SVPWM algorithm based DTC drive
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Fig. 6 Starting transients of a novel DZRCDPWM based DTC drive
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Fig. 7 Steady state plots of a novel DZRCDPWM based DTC drive
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Fig. 8 Locus of the stator flux for proposed PWM algorithm based DTC
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Fig. 9 Transients during step change in load for a novel DZRCDPWM based DTC drive
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Fig. 10 Harmonic spectra of line current for a novel DZRCDPWM based DTC drive
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Fig. 11 Transients during speed reversal operation for a novel DZRCDPWM based DTC drive
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